Thermal Islands

Topic(s):

Atmosphere, Biosphere, Climate, Energy, Weather

Scenario:

A heat wave in Chicago, increased thunderstorm activity in Quincy Illinois, and fogless London days and nights – is it possible these are all related to thermal islands? What is the role of cities in our climate – and more specifically, how does the urban heat island affect climate – not only in cities but in the surrounding countryside?

Numerous studies have shown how the concrete pavements and buildings retain heat in cities, making cities several degrees warmer than the surrounding countryside. The research of Tim Oke from the University of British Columbia has shown that cities of a million people can be 1 to 3 degrees Celsius warmer than the surrounding countryside during the day and as much as 12 degrees Celsius warmer at night.

Increased morbidity and mortality rates in cities during heat waves (sometimes referred to as Excessive Heat Events or EHEs) are exacerbated by the urban heat island effect. For this and other reasons, many believe mitigation of urban heat islands should be pursued. Some strategies being recommended include increasing trees and vegetation, and developing roofs that are green and/or cool.

As cities have grown, they have warmed. One result has been a decrease in fog. London, for example, used to be known for its "pea soup" fogs, but today, dense fog is rare in the city. New York, Tokyo and Los Angeles show similar trends. According to a November, 2005 article in Nature, changes in land cover in both cities and the countryside is responsible for part of the warming the United States has experienced in the past century.

In a 2003 paper in the Journal of Applied Meteorology , Rozoff, Cotton and Adegoke demonstrated how the urban heat island of St. Louis enhanced convective activity (thunderstorms) downstream of the city.

Not all the consequences of an urban heat island are negative. For example, savings in winter heating costs, less ice and snow, and longer growing seasons in urban areas are all positive results.

Task:

Your team has been approached by the congressional science committee interested in the impact of thermal islands on climate. Your ESS analysis of this possible connection will become an important part of their deliberations.

Basic: According to the National Resources Defense Council, heat waves contributed to the deaths of at least 225 people in the United States during July, 2006 NRDC Web Site . Assuming no mitigation strategies are initiated, determine how urban development will impact health, heat and climate during the next 50 years.

Comprehensive: The percentage of the world's population living in cities is increasing. Today, about 50% of the world's people live in cities. Some projections indicate this number will rise to 70% (of an overall population that is 50% larger than today) by 2050. There is a concern among policy makers that these trends in urban poulation and development, as well as local trends in climate change may enhance the thermal island effect of cities, resulting in increasing morbidity and mortality during heat waves. Because of a possible increasing magnitude of urban heat islands over the next 50 years, your team has been tasked to develop possible mitigation strategies.

Date: 1/22/2010

Scenario Images:

This image shows how both nocturnal and daylight temperatures vary in the vicinity of an urban heat island, and the fact that they have a different magnitude, especially in the daytime. More... Image: Courtesy: EPA (modified after Voogt, J.A., 2002: Urban heat island, in Vol. 3, Encyclopedia of Global Environmental Change, Ed. Ted Munn, John Wiley & Sons, Ltd, Chichester, 660-666)

Buildings, asphalt, concrete, and industry all contribute to the Urban Heat Island by their uptake and subsequent release of heat, and, in the case of industry, by adding heat to the atmosphere. More... Image: Courtesy NASA Earth Observatory

Resources:

3D Atlanta Heat Island
(Cycle A)
Very interesting animations of of Atlanta's heat island and the development of convective clouds in the heat island.

NASA's Earth Observatory
(Cycle A)
The Earth Observatory's mission is to share with the public the images, stories, and discoveries about climate and the environment that emerge from NASA research, including its satellite missions, in-the-field research, and climate models.

Heat Island Group
(Cycle B)
Describes the urban heat island including effects on air quality and energy use. Includes links to mitigation strategies including vegetation , cool roofs, and cool pavements.

Sample Investigations:

Feeling the heat
(Cycle A)
Students learn about the urban heat island effect by investigating which areas of their schoolyard have higher temperatures. Then they analyze data about how the number of heat waves in an urban area has increased over time with population.Difficulty: beginner

Measuring Temperature Islands
(Cycle A)
Goal is to identify both natural and urban heat islands and learn to use an infrared thermometer.Difficulty: beginner

Trees and air quality
(Cycle A)
Students investigate the ways in which trees benefit air quality and determine how to landscape a home with trees to decrease energy use.Difficulty: beginner

Weather and health
(Cycle A)
A COMET learning module that describes weather and health. The section on everyday weather includes heat waves. There is also a game on weather and health. Registration is required (free registration) on UCAR's meted website.Difficulty: beginner

Why is the city hot?
(Cycle B)
Examines the formation of urban heat islands with Atlanta as an example using NASA data.Difficulty: beginner

Mapping Local Data in GIS
(Cycle C)
From the Earth Exploration Toolbook. Explores the relation between land cover and surface air temperature.Difficulty: advanced

Weather and the Built Environment
(Cycle C)
A COMET learning module that describes weather and built environment. Includes a section on the urban heat island. Registration is required (free registration) on the Univerity Corporation for Atmospheric Research's (UCAR) meted website.Difficulty: advanced

Standards:

ScienceNational Science Education Standards - Science Content Standards
http://www.nap.edu/readingroom/books/nses/html/overview.html#content
The science content standards outline what students should know, understand, and be able to do in the natural sciences over the course of K-12 education.

K-12 UNIFYING CONCEPTS AND PROCESSESThe understandings and abilities associated with the following concepts and processes need to be developed throughout a student's educational experiences:

Evidence, models, and explanation

GRADES K-4 CONTENT STANDARDS

Science as Inquiry (Std A)

Abilities necessary to do scientific inquiry

Understanding about scientific inquiry

Physical Science (Std B)

Properties of objects and materials

Earth and Space Science (Std D)

Properties of earth materials

Changes in earth and sky

Science in Personal and Social Perspectives (Std F)

Personal health

Changes in environments

GRADES 5-8 CONTENT STANDARDS

Science as Inquiry (Std A)

Abilities necessary to do scientific inquiry

Understanding about scientific inquiry

Physical Science (Std B)

Properties and changes of properties in matter

Transfer of energy

Life Science (Std C)

Regulation and behavior

Science and Technology (Std E)

Understanding about science and technology

Science in Personal and Social Perspectives (Std F)

Personal health

Populations, resources, and environments

Natural hazards

Risks and benefits

GRADES 9-12 CONTENT STANDARDS

Science as Inquiry (Std A)

Abilities necessary to do scientific inquiry

Physical Science (Std B)

Interactions of energy and matter

Earth and Space Science (Std D)

Energy in the earth system

Geochemical cycles

Science in Personal and Social Perspectives (Std F)

Personal health

Personal and community health

Environmental quality

Natural and human-induced hazards

MathematicsPrinciples and Standards for School Mathematics, National Council of Teachers of Mathematics (NCTM), 2000
http://standards.nctm.org/document/prepost/cover.htm
This set of Standards proposes the mathematics concepts that all students should have the opportunity to learn. Each of these ten Standards applies across all grades, prekindergarten through grade 12. Even though each of these ten Standards applies to all grades, emphases and expectations will vary both within and between the grade bands (K-2, 3-5, 6-8, 9-12). For instance, the emphasis on number is greatest in prekindergarten through grade 2, and by grades 9-12, number receives less instructional attention. Also the total time for mathematical instruction will be divided differently according to particular needs in each grade band - for example, in the middle grades, the majority of instructional time would address algebra and geometry.

STANDARD 2: PATTERNS, FUNCTIONS, AND ALGEBRAMathematics instructional programs should include attention to patterns, functions, symbols, and models so that all students—

use symbolic forms to represent and analyze mathematical situations and structures;

STANDARD 5: DATA ANALYSIS, STATISTICS, AND PROBABILITYMathematics instructional programs should include attention to data analysis, statistics, and probability so that all students—

pose questions and collect, organize, and represent data to answer those questions;

interpret data using methods of exploratory data analysis;

develop and evaluate inferences, predictions, and arguments that are based on data;

STANDARD 6: PROBLEM SOLVINGMathematics instructional programs should focus on solving problems as part of understanding mathematics so that all students—

build new mathematical knowledge through their work with problems;

develop a disposition to formulate, represent, abstract, and generalize in situations within and outside mathematics;

apply a wide variety of strategies to solve problems and adapt the strategies to new situations;

monitor and reflect on their mathematical thinking in solving problems.

STANDARD 8: COMMUNICATIONMathematics instructional programs should use communication to foster understanding of mathematics so that all students—

organize and consolidate their mathematical thinking to communicate with others;

extend their mathematical knowledge by considering the thinking and strategies of others;

use the language of mathematics as a precise means of mathematical expression.

STANDARD 9: CONNECTIONSMathematics instructional programs should emphasize connections to foster understanding of mathematics so that all students—

recognize, use, and learn about mathematics in contexts outside of mathematics.

STANDARD 10: REPRESENTATIONMathematics instructional programs should emphasize mathematical representations to foster understanding of mathematics so that all students—

create and use representations to organize, record, and communicate mathematical ideas;

use representations to model and interpret physical, social, and mathematical phenomena.

GeographyGeography for Life: National Geography Standards, 1994

THE WORLD IN SPATIAL TERMSGeography studies the relationships between people, places, and environments by mapping information about them into a spatial context. The geographically informed person knows and understands:

How to use maps and other geographic representations, tools and technologies to acquire, process, and report information from a spatial perspective

PLACES AND REGIONSThe identities and lives of individuals and people are rooted in particular places and in those human constructs called regions. The geographically informed person knows and understands:

The physical and human characteristics of places

PHYSICAL SYSTEMSPhysical processes shape Earth’s surface and interact with plant and animal life to create, sustain, and modify ecosystems. The geographically informed person knows and understands:

The characteristics and spatial distribution of ecosystems on Earth’s surface

ENVIRONMENT AND SOCIETYThe physical environment is modified by human activities, largely as a consequence of the ways in which human societies value and use Earth’s natural resources, and human activities are also influenced by Earth’s physical features and processes. The geographically informed person knows and understands:

How human actions modify the physical environment

How physical systems affect human systems

TechnologyThe International Society for Technology Education
From http://www.iste.org and
http://www.edtech.sandi.net/index.php?option=com_docman&task=doc_download&gid=349&Itemid=229